fix(editor): remove misleading image line above stack actions (#1584)

Closes #1580. The Command Center header showed the first container's
image directly above stack-wide Start/Stop/Update controls, which implied
those buttons targeted one image. Remove the header image/digest row;
per-container ImageSourceMenu on each row remains.

docs/getting-started/introduction.mdx

@@ -48,7 +48,7 @@ Stacks can be pinned and grouped by label. Each row carries a compact status mar
 
 Opening a stack gives you the day-to-day workspace:
 
-- The identity header shows the node, stack name, runtime state, primary image, digest, and main action buttons.
+- The identity header shows the node, stack name, runtime state, and main action buttons.
 - Running stacks expose **Restart**, **Stop**, and **Update**; stopped stacks expose **Start** and **Update**. The overflow menu holds less frequent actions such as rollback, config scan, and delete.
 - Container rows show health, uptime, published ports, live CPU and memory, network activity, logs, and service actions.
 - The logs panel can run in **Structured** mode or **Raw terminal** mode.